feat: add animation begin support on web (danilowoz#280)

Author: nicholasyan

README.md

@@ -126,6 +126,7 @@ const MyLoader = () => (
 | **`style?: React.CSSProperties`** <br /> Defaults to `{}`        | React DOM only             |                                                                                                                                                                                                                                                                                                     |
 | **`uniqueKey?: string`** <br /> Defaults to random unique id     | React DOM only             | Use the same value of prop key, <br/>that will solve inconsistency on the SSR, see more [here](https://github.com/danilowoz/react-content-loader/issues/78).                                                                                                                                        |
 | **`beforeMask?: JSX.Element`** <br /> Defaults to null           | React DOM<br/>React Native | Define custom shapes before content, <br/>see more [here](https://github.com/danilowoz/react-content-loader/issues/266).                                                                                                                                                                            |
+| **`animateBegin?: string`** <br /> Defaults to `undefined`              | React DOM only             | Delay before the animation begins, identical to the [SVG animate element begin attribute](https://developer.mozilla.org/en-US/docs/Web/SVG/Attribute/begin)
 
 See all options [live](https://danilowoz.com/react-content-loader/)
 

docs/index.stories.tsx

@@ -468,3 +468,23 @@ export const BeforeMask = () => {
     </>
   )
 }
+
+/**
+ * Animation begin delay
+ */
+export const animateBegin = () => {
+  return (
+    <>
+      <SyntaxCode>{' <ContentLoader animateBegin="5s" />'}</SyntaxCode>
+      <ContentLoader animateBegin="5s" />
+    </>
+  )
+}
+
+animateBegin.story = {
+  parameters: {
+    notes: `##\`animateBegin?: string\` 
+    
+    Defaults to \`0s\`. This attribute accepts the same values as the SVG animate element's [\`begin\` attribute](https://developer.mozilla.org/en-US/docs/Web/SVG/Attribute/begin).`,
+  },
+}